This invention relates to improvements in a bushing which is used for electrical equipment filled with an insulating material. The interior of the bushing communicates with that of a vessel receiving the electrical equipment therein, and is filled with a gaseous insulator under a high pressure. It is therefore feared that, when a porcelain tube or wall tube insulator constituting the bushing becomes damaged, its fragments will scatter around to cause a secondary accident wherein the porcelain tubes of the adjoining bushings will be damaged in a chain reaction. There has not been any prior-art bushing with a structure appropriate for preventing such accidental damage to the porcelain tubes.